The three main roles are nitrate, nitrite, and denitrify. Nitrite is in the soil, and turns useful stuff into nitrate. Nitrate takes the useful stuff, is eaten by animals, and is decomposed. Denitrify is when once the animals release nitrate, it takes it back out and is released in the atmosphere.
I actually believe there are three. They are the main setting (background and/or conflict setting), the main characters and their roles (depending on the assignment) but most importantly the BASIC conflict.
The cast of Three of a Kind - 1967 includes: Lulu as Various roles Audrey Bayley as Various roles Malcolm Clare as Various Roles Ray Fell as Various Roles Alix Kirsta as Various roles Frances Pidgeon as Various roles Christine Pockett as Various roles Mike Yarwood as Various Roles
Proteins have the very important function of building muscle in the body, but not just that, they also play several important roles for the human body. They are the main components of structures as skin and hair, they are in charge of the hormonal regulation and also are part of the immune system.
If you are referring to CAT as in citizen advancement training, there are three main components to the process whether it is newly structured or not. These are military orientation, community service and public safety, and law enforcement service.
Parliament consists of three parts, the house of commons, the senate and the monarch. Its main roles are to create new laws and modify existing ones to make them the best they can be for Canadian citizens.